It may be beneficial for a device comprising a lens to adjust the path of incident optical and/or acoustic waves by adapting the properties of the lens. For example, in a conventional camera, a lens may be adjusted via a motor and gear assembly to allow the camera to focus on an object that is closer or further away from the camera. When the camera optics perform a zoom by narrowing or expanding the field of view, mechanical components in the camera assembly may move one or more lenses to cause the camera optics to properly focus the image captured by the camera.
Some lenses may utilize an anisotropic birefringent crystal to adjust optical and/or acoustic properties. For example, a liquid crystal has optical properties that may be adjusted by applying an electric field to the liquid. Thus, the properties of light and/or sound passing through the liquid may be modified. However, other properties, such as the polarization state of light, may also be modified in the process.
Some lenses may adapt optical and/or acoustic properties by moving a fluid within an electric field. For example, electrowetting techniques move an interface of hydrophilic and/or hydrophobic fluid droplets by applying an electric field to the droplets, thus moving one of the fluids towards or away from an optical path of a lens. However, the effectiveness of such an approach may be highly sensitive to the angle of light and/or sound incident upon the lens. Moreover, since the amount of force that may be applied to such droplets may be small, devices utilizing this technique may be limited to small lenses.